During the lifetime of a wind turbine, considerable resources are expended on continued maintenance operations to ensure optimum turbine performance. With regard to the blades of a wind turbine, erosion at the leading edge of the blades is one area of attention.
It is known to provide an erosion shield at the leading edge of a wind turbine blade. The erosion shield comprises a layer or coating of resilient erosion resistant material which is applied along the length of the blade covering the leading edge. The erosion shield provides improved resistance to erosion, being usually formed of a resilient material as opposed to the relatively brittle fibre composite material used to produce the body of a wind turbine blade, and accordingly acts to improve the overall durability of the wind turbine blade. An example of an erosion shield comprising a polymeric film can be seen in EP 2 153 065.
Field experience has shown that such erosion shields or erosion tapes will last approximately between 5-8 years, depending on the environmental conditions of the location of the wind turbine, as well as the turbine operating conditions, especially blade tip speed. However, when the erosion resistant layer ruptures due to heavy erosion, in general there will be portions of the layer left on the turbine blade to freely flutter in the wind. This fluttering will result in a loss of aerodynamic performance of the blade, as well as the generation of additional aerodynamic noise.
In the case of such a rupture of the erosion shield, such reduced turbine performance will continue until a maintenance operation is performed to remove the ruptured shield. This involves an extensive and complicated operation to stop operation of the turbine, remove the ruptured shield from along the leading edge of the turbine blade, and to apply a new erosion shield along the leading edge.
It is an object of the invention to provide an erosion shield for a wind turbine blade which reduces the problems associated with shield rupture, and requires reduced maintenance.